Routine diagnostic testing is imperative for the early detection and treatment of HIV infection. Because individuals are at higher risk for transmitting the virus during early or acute infection, accurate and timely diagnosis may reduce the transmission of HIV when the individual is most infectious (Wawer et al., J. Inf. Dis. 191:1403-1409, 2005). Early detection of HIV has been shown to lead to reduced high-risk behavior and to connect individuals to treatment earlier, which can reduce transmissible virus (Branson et al., Morbidity and Mortality Weekly Report 55:1-17, 2006; Marks et al., J. Acquired Immune Deficiency Syndromes 39:446-453, 2005). Although there are currently several FDA-approved HIV diagnostic tests available, there are still 1.1 million people in the U.S. living with HIV, of which 15.8% are undiagnosed or unaware of their infection status (CDC HIV Surveillance Report, 18:1-47, 2011).
For accurate and early detection of HIV-1, as well as HIV-2, a revised HIV laboratory testing algorithm has been developed. In this algorithm, specimens are screened with a sensitive HIV-1/2 immunoassay, preferably a fourth-generation antigen/antibody assay, followed by an HIV-1/2 differentiation assay. Specimens that are non-reactive are considered negative. Specimens that have concordant reactivity on the screening and supplemental test are considered positive for HIV-1/2 antibodies; however, in the case of discordant immunoassay results, HIV-1 nucleic acid amplification testing (NAAT) is recommended. NAAT generally is highly sensitive, virus-specific, and allows for detection of infection approximately two weeks earlier than most antibody-based tests (Schito et al., J. Inf. Dis. 201(Suppl. 1):S1-6, 2010).
To date, there are no definitive guidelines for HIV testing at the point-of-care (POC). POC testing has increased the number of individuals who are screened for HIV and receive their HIV test results (Schito et al., J. Inf. Dis. 201(Suppl. 1):S1-6, 2010). Rapid tests have facilitated HIV testing at the POC because they can be completed in a short period of time (typically 30-60 minutes) and require minimal technical expertise. Currently, there are a number of rapid antibody tests available that are FDA-approved; however, they are not as sensitive for detection of early HIV infection as most are laboratory-based assays and remain negative during the post-infection, but pre-seroconversion period (Wesolowski et al., J. Clin. Virol. 58:240-244, 2014).